Boiler furnace



April 16, 1929. G. T. LADD 1,709,356

301mm FURNACE Filed lie-1724, 1926 2 Sheets-Sheet 1 INVENTOR ATTORNEY s A ril 16, 1929. G. T. LADD BOILER FURNACE Filed May 24, 1926 2 Sheets-Sheet ATTORNEYS Patented Apr. 16, 1929.

UNITED STATES PATENT OFFICE.

enonen T. L'Am), or PITTSBURGH, PENNSYLVANIA, ssmnon To LAnn wATnn TUBE BOILER comrmr, or new YORK, 11. Y., A CORPORATION or DELAWARE BOILER FURNACE.

Application filed May 24,

This invention relates to boiler furnaces,

and is particularly useful where the fuel is to be burned in suspension, as, for example, where the fuel is in pulverized form.

t The invention has to do with that type of boiler which is constructed in the shape of a furnace, and is, in fact, its own furnace.

One of the primary objects of the invention is to simplify the c'wnstruction, to rem duce the number of parts, and to reduce the size ofcertain parts, whereby the costs are very materially reduced and the size of the installation decreased, as will hereinafter appear, while,at the same time, the installa- 215 tion has a very large capacity, as compared to standard boilers. I obtain the foregoing, together with such other objects and advantages as may hereinafter appear, or are incident to m invenac tion, by means of a construction whic I have illustrated inthe preferred form in the accompanying drawings, wherein' Fig. ,1 is a vertical section through a boiler furnace embodying my invention, and Fig.2 is a vertical section through a modified iiorm of boiler furnace.

Referring now to Fig. 1-, the reference character A denotes the boiler furnace considered as a whole, the boiler defining the combustion space properB, beneath which there is a settling chamber C formed by the setting 3. g

The boiler com rises the drums 4 and 5 which maybe of t e usual diameter, and the 135 headers or small drums 6 and 7; the front water wall a composed of longitudinally finned tubes 8, connected at their upper and lower ends into theupper and lower small drums or headers 6 and 7, respectively; the side water walls 6 composed of longitudinally finned tubes'i) connected at their upper and lower ends into the upper and lower headers 10 and 11, respectively, the upper headers 10 being connected into the drum 4e 4 and the lower headers 11 being connected into the drum5; the roof water wall 0 composed of longitudinally finned tubes 12 connected at one end into the small drum 6, and at the other end into the drum 4;-the rear watervwall d composed oflongitudinally finned tubes 13 connected at their upper and lower ends into the drums 4 and 5, respectively; the bank of tubes 14 connected at one end into the-drum 5, and at. the other end 1956. Serial No. 111,156.

into the small drum 7; and the upright bank of tubes 15 connected at their upper and lower ends into the drums 4 and 5, respectively.

'In connection with the headers 6 and 7 and the drums 4 and 5, it is pointed out that the headers 6 and 7 are more closely spaced than are the drums 4 and 5, and that the u per header 6'is below the level of the upper rum 4. By this arrangement the tubes 12 of the roof wall a constitute upcomers from the upper header 6 .to the upper drum 4, by virtue of which only one upper drum need be employed, and the usual upper steam drum is dispensed with, and, consequently, the cost of the installation is reduced. It will be observed that the diameter of the drums 6 and 7 of the front wall may be greatly reduced by'this arrangement which further reduces the manufacturing costs of the installation.

The bottom of the combustion chamber B is bounded by the bank of tubes 14, the tubes of which are sufficiently spaced apart to allow any refuse particles precipitating out of the fuel to pass therebetween to the settling chamber C. The precipitating ash is cooled below slag forming temperature by these tubes.

Althou h the waste gases of comlnistion passing t rough the bank of tubes 14, are cooled somewhat by these tubes, they are not, however, cooled below the temperature required to superheat the steam passing through the superheater 16 located in the path of the waste gases from the chamber C to the ofl'take 17. The superheater 16 is located between the upright bank of tubes 15 and the rear water wall al of the boiler. The products of combustion, after passing over the superheater elements 16, pass over the bank oftubes 15, suitable baffling being provided to direct the course of the gases. After passing over the bank of tubes 15, the gases pass into the breaching 18, in which a combustion air preheater 19 is located. Thus, it will be seen that the superheater 16 is so located as to be sub ject to gases-of'high enough temperature to obtain the proper degree ofsuperheat, and that the air heater is not subjected to ases of such hightemperatures as would urn out the elements thereof, because of the introduction of convection surfaces, namely, the bank of tubes 15, between the superheater and the air preheater, which tend I to pull down the'temperature of the gases after they leave the superheater. This arrangement is'of great importance, as the gases leave the combustion space proper at relatively very high'te'mperatures, this being above pointed out. In addition, the main- "tenance of high, temperatures in the combustion space proper is of great importance in ensuring eifective combustion.

The bank of tubes 15 constitutes the economizer section of the boiler, and is an integral part therewith by reason of the tubes connecting ,at their ends into the drums at and 5 of the boiler. The tubes of thisbank of tubesbecome the downcomers of the boiler, the circulation in the tubes of the water walls and in the tubes of the bank of tubes 14 being in an upward direction. Thus, the necessity for the usual outside downcomer tubes with their lagging is obviated, which enables me to decrease the length of the drums, and, consequently,

reduce the width of the boiler, and, at the same time, efi'ecting a saving 1n manufacturing costs. The cost of drums, particularly where the pressures are relatively high, is an important economical factor.

The fuel to be burned jSjliitIOdllCQd at. the four corners of the combustion chambers by means of the burner nozzles 20, prefera ly located at the upper portion of the combustion chambers. l-lighly preheated combustion air is introduced with the fuel through the medium of the air openings 21 surrounding the burner nozzles 20, the preheated air bein taken from the air heater 19 by the nets 22 leading to the burners. Thus the fuel and air is introduced in a manner to produce vortical mixture and combustion, the combustion being intense and. turbulent, whereby a high flame temperature and short length of flame travel is obtained.

lteferrin now ,to the modification illustrated in ig. 2 it will be seen that l have provided what may be termed a double type of boiler furnace, by positioning two boiler furnaces, of substantially the same construction as that shown'in Fig. 1, with the front water walls a, a, adjacent to one another. However, instead of connecting the lower ends of the tubes of each of the water walls a into a separate header, l have connected them into a common drum 7*. The tubes of the side walls I; in this instance, as before, are connected at their upper and lower ends into headers, and the upper headers 10 are each connected into their corresponding upper drums at, but-the lower combustion space being formed of an upper drum, a lower drum, and tubes connecting into said drums, the front wall being formed of an upper header, a lower header, and

tubes connecting into said headers, said.

front wall headers being more closely spaced than the rear wall drums the upper header being below the level of the upper drum and the lower header being above the level of the lower drum, tubes connecting the lower drum and lower header, tubes con necting into the upper drum and upper header, and a bank of tubes exterior to the combustion space connecting into the upper drum and the lower drum.

- 2. A'tubular boiler-furnace having the combustion space primarily defined by tubes subject to radiant heat, the rear wall of said combustion space being formed of an upper drum, a lower drum, and tubes connecting into said drums, the front'wall being formed of an upper header, a lower header, and tubes connecting into said headers, said front wall headers being more closely spaced than the rear wall drums the upper header bein below the level of upper drum and t e lower headerbeing above the level of the lower drum, tubes connecting the lower drum and lower header, tubes connecting into the upper drum and upper header, and a bank of tubes exteriorto the combustion space connecting into the upper drum and the lower drum, together with means for admitting. pulverized coal and combustion air for turbulent combustion, and an odtake for the products of combustion beyond the aforesaid bank of tubes.

3. In a pulverized fuel burning installation a boiler comprising a pair of u per drums, a pair of upper headers interme iate but below the level of said drums, a pair of lower drums, a lower drum intermediate and above the level of said'pair of lower drums, upright tubes connected into one upper and one lower drum of said pairs of drums, upright tubes connected into the mouse tubes connected with one'drum of the upper pair of drums and the intermediate lower drum, upright tubes connected with the other upper drum and said intermediate drum, said upright tubes constituting water walls for the upright walls of two combustion spaces, a roof wall for each combustion space composed of tubes connected into the upper drums and the upper headers, tubes marginal of the bottoms of said combustion spaces connected between the pair of combustion space primarily defined by tubes sulg'ect to radiant heat, the rear wall of sai combustion space being formed of an upperdrum, a lower drum, and tubes connecting into said drums, the front wall being formed of an upper header, a lower header, and tubes connecting into said headers, said front wall headers being more closely spaced than the rear wall drums, the upper header being below thelevel of the upper drum and the lower header being abovethe level of the lower drum, tubes connecting the lower drum and lower header, tubes connecting into the upper drum and upper header, other tubes connecting the up r and lower drum and constituting the so e downcomers for the boiler and means for shielding said other tubes from radiant heat of the combustion space.

In testimony whereof I have hereunto signed my name.

GEORGE T. LADD. 

